Tube leakage testing machine



March 30, 1954 K. R. THOMPSON TUBE LEAKAGE TESTING MACHINE 5 Sheets-Sheet l Filed April 19, 1949 March 30, 1954 K. R. THOMPSON TUBE LEAKAGE TESTING MACHINE Filed April 19, 1949 3 Sheets-Sheet 2 INVENTOR. /ez 725077076077.

March 30, 1954 K. R. THOMPSON 2,673,462 TUBE LEAKAGE TESTING MACHINE Filed April 19, 1949 3 sheets-sheet s Patented Mar- 30, 1954;

TUBE LEAKAGE TESTING MACHINE Keithv R. Thompson, Monroe..Miclr., assignorto Monroe Auto Equipment" Company, Monroe.. Mich., acorporation'of Michigan Application' April 19, 1949; Serial No; `88.250

3 Claims.

This invention relates to devices thattest for leakage of tubes or other hollow parts.

It is an object of the invention to provide a tube leakage testing device that requires a minimum of human skill to operate.

Another object is to provide such a device that may be easily and rapidly operated.

A further object is to provide a device in which optimum conditions are present for the observation of the escape of uid pressure from a tube being tested.

An additional object isto provide such a device in which the testing bath is not appreciably disturbed by.v the escape` of pressure fluid during loading and unloading operations.

Other objects of the invention will appear in the detailed description to follow. Generally, the improved tube leakage tester comprises a cradle'for the tube which is lowered into or raised out of the testing bath by means of a pressure inder and seal the tube. Further movement of the cradle actuates a third valve to admit pres-- sure fluid to the tube. Upon the operators re'- lease ofthe rst valve, the cradle cylinder lifts the-cradle outof the bath and during this movement the third and then the second valves are opened to exhaust the tube and then unseal it'so that the operator'can remove it andload another on the cradle.

A preferredA embodiment of 'the invention is shown by way of illustration in the accompanying dra-wings in which:

Figure 1 is a perspective view of the improved tube leakage testing device;

Fig. 2 is a longitudinal section taken' just inside the tank of Fig. l and shows the cradle mechanism in side elevation;

Fig. 3 is a plan view of the device;

Fig. 4 is a cross section taken cn.line.4-4 of Fig. 2;

Fig. 5 is a cross section taken on linel 5-5 of Fig. 3; and

Fig. 6 is a cross section taken on line 5-6 of Fig. 3.

Any suitable means for providing a testing bath may be utilized in conjunction with the presentlinvention. A preferred form is shown in Fig. 1 as comprising a rectangular tank I having an open top 3 and' corner legs Svthati support itA Movement ofv the cradle actuates a second valve to control the secondpressure cyl-` i is fixed' to the web of the channel 23 and by aV at a convenient' height aboveV the` floor. Water' may beI fedi into the tank I and maintainedata.. desired level through-the medium. of a standpipei T (Fig. 2). A light 9 may be employed tozshine through a suitableY sealed? aperture II inY a: side of the tank to illuminate the interior and facili` tate the detection of air bubbles escaping from.' tubes'being tested. in thebath, the level. ofY the; bath being indicated atv I3;

The xture4 or cradle I4 for holding tubes to be testedlmay be mounted upon aplate I5 thatrests on thelbottom of tankv l. as'shownor'may betattached to the bottom of thetank. The cradle. I4A includes short longitudinal. side legs. IQ1" that.

' are pivoted at one end to` a bracket' I9 thatl isY mounted onthe` plate I5', asshown.at.2|`. The legs Il are welded to theilanges of a channel?` beam 23 which: formsthe majormemberot` the: cradle- I4. The web of the channel 23 may have a rib 25 suitably afxed thereto and extending somewhatv below the flanges thereof (Figs. 2V and 5).

The-tubes A illustrated are used in shock absorbers and have an opening B at one end andl a looped cap or closure Cat the other. TheV cap C is welded to thetube-A and theA test provided by the present device is intended primarily to determnethe quality of this'weld. The-tube is supported on the cradle I4' by a V block 21 that V block 29 that forms one end of an adjustable support 3'I. The support includes side legs 33 which are in juxtaposition'to the'langes of channel 23'l and which interconnect the V blockv 294 and an upright'memb'er35` that has pads 31' of rubber or other-suitable gasket material affixed to its vertical face. The pads 31 are adapted to engage and seal the open end B of a tube A that is supported on the V blocksv 21V and 23. The support 3lli rests, of course, on the web of the channel 23 by virtuetof the block 21. and member 35. Itis removably fixed against movement away from block 21 by means of aspringpressed pawl lever, 39v that is pivoted at 4I' to suitable ears extending from the lower'face cfa lJ.-shaped one end of the cylinder controls the position of the piston rod 49 and adapter 41. Thus, in addition to the air inlet line 51, the valve 55 also has an exhaust conduit 59 and the communication of either of these conduits with the cylinder I is under the control of the valve plunger 6I, this type of valve being a conventional item which may be purchased on the open market. It will be observed that the valve 6I extends beyond the left end of the bracket I9 to which the cradle is pivoted and therefore moves in an opposite direction to a tube A supported on the cradle. It is desired to energize the cylinder 5I so as to drive the adapter 41 to the right and slide the tube A on its supports 21 and 29 against pads 31 and therefore seal the opening B upon downward movement of the cradle I4. To accomplish this the valve 55 is arranged so that the plunger 6I is ordinarily biased to permit communication of the pressure conduit 51 with the cylinder. On the other hand when the cradle is moved upwardly out of the bath it is desired to exhaust air from the cylinder 5I so that the axial force sealing the tube A is released. This is effectuated by upward movement of plunger EI relative to the valve 55, and is accomplished by a stop 63 of adjustable length that is secured to the plate I5 which limits downward movement of the plunger BI as the cradle I4 is pivoted up out of the bath. If desired a lever 64 may be inserted between the plunger 6I and stop 63 to engage each.

Means are provided to automatically admit pressure air for testing purposes to the tube A after it has been sealed against the pads 31 and to exhaust such air from the tube after it has been tested and before it is unsealed or released from the pads 31 by de-energization of cylinder 5I as just described. For this purpose the member 35 and pads 31 have a fluid passage 55 which is in alignment with the tube opening B and therefore communicates with the interior of the tube A. A conduit S1 attached to the member 31 in communication with passage 95 provides means for the flow of testing pressure air to and from the tube. Flow through the conduit 91 is under the control of a suitable plunger operated three way valve 69, which may be carried by the tank I as shown, procurable on the open market. Air under pressure is admitted to the valve 69 through conduit 1I and air from the tube is exhausted from the valve 69 through a conduit 13 which preferably has its outlet outside the tank as shown so as to prevent agitation of the testing bath due to the release of pressure air from the tube. The valve plunger connects the pressure line 1I to the tube conduit 61 when it is depressed but in its normal biased upward position it connects conduit 61 to the exhaust line 13. 'Ihe valve 69 is located adjacent a stop and support 11 for the free end of the cradle channel 23 so that the latter depresses the plunger 15 and thereby admits pressure test air to the tube A when it reaches its position of rest in the test bath. When the cradle I4 is pivoted upwardly, the free end or channel 23 releases the plunger 15 so that air in the tube A is exhausted through conduit 'i3 before the plun'rer 6I is actuated to initiate unsealing of the tube end B.

lil

The cradle I4 ls biased upwardly out of the bath by a compression spring 8l that rests between the web of channel 23 and the plate I5. While the cradle I4 may be manually pivoted, a pressure cylinder 83 is preferably provided for this purpose. This cylinder is suitably mounted on a bracket 85 that may be secured to the sides of the tank I. The piston rod 81 of the cylinder is pivoted at 89 to the free end of the channel 23. Pressure is admitted to opposite ends of the cylinder 83 by conduits 9I and 93 and these are controlled by a four way foot valve that has a pressure line 91 and an exhaust line 99. The pressure line 91 and the pressure lines 51 and 1I for valves 55 and 69 may be interconnected by a T IUI that receives pressure air from a suitable source through line |03.

In operation the cradle I4 is normally in the dotted line position of Fig. 2 due to the pressure of spring 8l and the arrangement of valve 95 which normally connects conduit 93 to the pressure line 91. The tube A is laid on the V blocks 21 and 29. The valve 95 is actuated by depression of the foot pedal so that line 93 is connected to exhaust line 99 and Lne 9| to pressure line 91. This forces the rod 31 downwardly and therefore moves the cradle I4 toward the bath. When this movement begins, the plunger 6I of Valve 55 is depressed by contact with stop 63 but shortly thereafter it is released to convert the pressure line 5? to the cylinder 5I and therefore drive rod 49 and adapter 41 to the right. This forces the tube A against pads 31 and seals the opening B. When the tube A is completely submerged in the test bath, the channel 23 depresses the plunger 15 and the valve 69 passes pressure air from line 1I to llne G1 and thus into the tube A.

After the operator has ascertained by the presence or absence of bubbles escaping from the tube A whether or not it is faulty, he releases the foot valve 95. This connects line 9I of the cylinder 83 to exhaust and the line 93 to pressure line 91 so that the rod 81 lifts the free end of the cradle. As this upward movement begins the plunger 15 is released and the valve 69 connects the line 61 and thus the interior of tube A to line 13 which permits the air to flow directly to the outside of the tank so as not to violently agitate the test bath. After this has taken place, the upward movement of the forward portion of the cradle I4 causes the plunger 6I to move downwardly against the stop 63 to connect the cylinder 5I to the exhaust line 59 and thereby unseal the tube A so that it may be removed from and a new one inserted in the cradle I4.

Various modifications are within the scope of the invent'on it being especially evident that the device may be employed to submerge more than one tube at a time in the testing bath.

What is claimed is:

l. In a device for testing leakage of tubes having predetermined end openings the combination of means adapted to contain a testing bath, an elongated cradle pivoted adjacent one end for slidably support'ng tubes to be tested, means for moving one end of the cradle into and out of the bath, members on the cradle for engaging the ends o.` a tube supported thereon so that the tube is supported on its side and movable sideways into the bath, one of said members being adapted to seal the ena1 openin: in the tube, one of said members being moable lengthwise of the tube, a pressure cylinder on the cradle f-rr moving the mavftbe :net i'cr aga'nit the ttbe to eppfy ax al force thereto to elfectuate sealing engagement of the sealing member with the tube portion surrounding said opening and for moving the movable member away from the tube to eiectuate unsealing, a valve controlling the pressure cylinder, said valve being operated by the cradle to seal said end opening when the latter has been lowered to a predetermined position in the bath and to unseal said end opening when the-cradle is lifted above such position, and means including a valve for admitting pressure fluid to and eX- hausting it from the tube through the sealing member and tube opening, said last valve being operated by the cradle to admit air after the tube has been sealed and to exhaust air to atmosphere before the tube has been unsealed and before the cradle is lifted out of the bath.

2. In a hollow part leakage testing device having a tank adapted to contain a testing bath, the

combination of an elongated cradle pivoted adja cent one end in the tank whereby the free end of the cradle is movable into and out of the testing bath, means for pivotally moving the cradle, a member carried by the cradle for sealing a predetermined opening in the part to be tested, a fluid passage in said sealing member in alignment with the part opening whereby iiuid may communicate with the interior of the hollow part, a source of pressure air, means including a valve connecting said source with said passage, said valve having an exhaust port vented to atmosphere and being normally arranged to connect the passage with the port, said valve being mounted in the tank beneath said cradle and having a control element engaged by the cradle only in its substantially fully lowered position to operate said valve so as to connect the passage with the source.

3. In a hollow part leakage testing device hav- 6 ing a tank adapted to contain a testing bath, the combination of an elongated cradle pivoted adjacent one end in the tank whereby the free end of the cradle is movable into and out of the testing bath, means for pivotally moving the cradle, a member carried by the cradle for sealing an opening in one end of the part, a pressure cylinder having a rod movable toward and away from said sealing member, an adapter mounted on the rod for engaging the other end of the part and forcing the part against the sealing member upon movement of the rod, a valve for operating the pressure cylinder and including a control element, means actuated by movement of the cradle for operatively engaging the control element when the cradle is in an intermediate position between its ultimate raised and lowered positions, a fluid passage in said sealing member in alignment with the part opening whereby uid may communicate with the interior of the hollow part, a source of pressure fluid, means including a valve connecting said source with said passage, said last mentioned valve having an exhaust port and being normally arranged to connect the passage with the port, said last mentioned valve being mounted in the tank beneath said cradle and having a control element engaged by the cradle only in its substantially fully lowered position to operate said valve so as to connect the passage with the source.

KEITH R. THOMPSON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,378,215 Burns May 17, 1921 2,391,351 Schmidt Dec. 18, 1945 2,532,954 Sherer Dec. 5, 1950 

